This invention relates to a power generating display.
Computers and electronic devices typically present visual information to users through display devices. In particular, liquid crystal displays (LCDs) are used extensively in watches, calculators, radios, laptop computers and, more recently, in flat screen and projection television systems. For desktop applications, LCD monitors provide a number of benefits; sharp text, thin profile, lower power consumption, less heat generation, and no VLF or ELF emissions to raise health concerns. Small size has always made LCD monitors popular in settings, such as financial and medical installations, where space is at a premium. But a number of other factors are also in their favor. LCD monitors are direct-address displays, which means that each pixel corresponds to a physical display component in the panel. Consequently, images are displayed with greater precision than in a CRT. And since the LCD cells are always in perfect alignment and position, they do not suffer from problems with screen geometry (such as pincushion distortion) or convergence error, which occurs when an imperfect electron beam creates halos around the edges of an on-screen object. For portable applications, LCDs offer significant power and weight reduction over corresponding cathode ray tube (CRT) displays.
Current displays are predominantly Active Matrix Liquid Crystal Displays (AMLCDs). These displays typically require a light source that emits light from behind them. Further, they also absorb a significant amount of this light, so only a portion of available light gets through to the display. As display devices represent a significant portion of the power consumption for a typical portable machine, display devices with low power consumption are needed. Further, due to the excessive heat generation of CRTs, even desktop computers require low-power and thin display devices.
In one aspect, a power-generating active-matrix display includes a first region having a plurality of solar cells arranged in a matrix; and a second region having a plurality of thin film transistors, each of which is associated with a pixel electrode and wherein the solar cells overlie respective pixel electrodes.
Implementations of the above aspect may include one or more of the following. The solar cells of the power-generating active-matrix display are electrically coupled together. The solar cells can capture photons from a photon source external to the display. The display can include a backlight positioned below the solar cells and the pixel electrodes, and the solar cells can capture photons from the backlight. The solar cells allow radiation from the backlight to go through the pixel electrodes. The solar cells can transmit light from the backlight while capturing photons from a photon source external to the display. The solar cells can have a thickness that is a quarter wavelength of light to enhance reflection of light from a conductive film below. The solar cells can be amorphous silicon (a-Si) cells. The solar cells and the thin film transistors can reside on one layer. A plurality of facing electrodes are positioned below the pixel electrodes, and a liquid crystal layer is positioned between the facing electrodes and the pixel electrodes, wherein the facing electrodes and the pixel electrodes apply a vertical electric field to the liquid crystal layer. A plurality of second solar cells can be arranged in a matrix and occupying the same layer as the polarizer above the facing electrodes. The polarizer absorbs 50% of the incoming light, so it is well suited for solar collection. Each facing electrode can include red, blue and green filters and electrodes to display color. The red, blue and green electrodes can be disposed in a delta-arrangement. A voltage regulator can be connected to the plurality of solar cells to provide regulated power. The device includes an antireflecting coat (ARC). The ARC transmits lights under the display to a viewer and reflects sunlight to amorphous silicon, effectively acting as a two way mirror. More than one layer of the solar cells can be stacked to increase collection and reflection efficiency.
In another aspect, a method for displaying an image and generating power includes transmitting light using an antireflecting coating under the display to a viewer; and reflecting sunlight to an amorphous silicon solar cell embedded in the display. The power output of the amorphous silicon can be collected and regulated.
Advantages of the invention may include one or more of the following. The power-generating LCD emits light without requiring external power when sunlight is shining on the LCD. The LCD reflects the bulk of the light to the user""s eye. This is achieved by incorporating a solar cell in the display, wherein the solar cell captures light from the ambient to provide backlight or to recharge the batteries. The solar cell also recycles some of the power spent by the LCD backlights. The display also efficiently utilizes absorbed backlight and generates useful power from the backlight by recycling the energy absorbed by the polarizer. A high performance, low overhead system for wireless communication system expanding the functionality and capabilities of a computer system is provided. The system effectively combines multiple components required to generate power and display images into a single integrated circuit device. The complete integration of components greatly reduces manufacturing costs. The system provides for fast, easy migration of existing designs to high performance, high efficiency single chip solutions.